The fabrication of a semiconductor device involves a plurality of discrete and complex processes. The semiconductor substrate typically undergoes many processes during the fabrication process. These processes may occur in different processing chambers, which may be maintained at different processing conditions. In certain embodiments, a transfer chamber is used to transport the substrates between these processing chambers. A substrate handling robot is disposed in the transfer chamber and moves the substrate from one processing chamber to another processing chamber. Additionally, the substrate handling robot may move the substrates to and from a load lock, which separates the transfer chamber from the external environment.
Heating substrates before and/or after processing is common in many semiconductor fabrication processes. In many cases, the substrate is heated to a temperature close to the process temperature and then transported to the processing chamber. This preheating may help prevent substrate warping, popping and movement when the cold substrate contacts the hot platen. These phenomenon may cause the creation of particles and mishandling, and may reduce overall process yield.
Additionally, in some embodiments, a substrate may be warmed after being subjected to a cold process to eliminate the possibility of condensation when the substrate exits the transfer chamber.
In many embodiments, this heating of the substrate is performed using a preheating station. The preheating station may comprise one or more infrared lamps that are focused on the substrate. While the preheating station is effective at raising the temperature of the substrate, it has a negative impact on throughput. Specifically, a substrate may be deposited at the preheating station for a significant amount of time in order for the substrate to reach the desired temperature. This increases the time that the substrate remains in the transfer chamber. Further, once the substrate is removed from the preheating station, it begins to cool. For example, in some instances, the substrate may cool up to 50° C. or more as it is being transported from the preheating station to the processing chamber. Thus, the substrate may not be at the desired temperature when the substrate is finally placed in that processing chamber.
Therefore, it would be beneficial if there were a system and method of heating a substrate while the substrate is being transported between processing chambers. Further, it would be beneficial if this heating could be accomplished without adding additional processing time to the fabrication process.